Endothelial cell activation in vasculitis of peripheral nerve and skeletal muscle.

To clarify the role of endothelial cells in the pathogenesis of vasculitis affecting peripheral nerve and skeletal muscle, the endothelial expression of adhesion molecules and major histocompatibility antigens (MHC) in different vasculitic syndromes were studied, and related to the presence of anti-endothelial cell antibodies (AECA). Increased expression of the intercellular adhesion molecule ICAM-1 in vasculitic lesions in nerve and muscle was shown, and this was associated with increased expression of MHC class I and II antigens. AECA were detected in low titre in only a minority of patients. The findings suggest that endothelial cells have a critical role in mediating the tissue injury in vasculitis affecting nerve and muscle and that the process is triggered by cellular and not antibody-mediated mechanism in the majority of patients.